Strip thickness control apparatus



March 19, 1963 K1N 3,081,653

STRIP THICKNESS CONTROL APPARATUS Filed Nov. 22. 195'? 22 Screwdown 00M 24 Device Down Device Pulse Pulsg Generator 7 Counter Strip Taper Control Device Program Control 48 4. Length Of Single Strip STREP TtiiCKNESS CONTRUL APPARATUS Norman L. Kincaid, Buiiaio, N.Y., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa, a corporation of Pennsylvania Filed Nov. 22, 1957, Ser. No. 698,188 2 Claims. (1. Sit-56) The present invention relates, in general, to strip thickness control apparatus, and more particularly to strip thickness control apparatus for controlling the thickness of a strip along its length relative to any predetermined taper or thickness changes and/ or thickness pattern that may be desired.

It is an object of the present invention to provide improved strip thickness control apparatus operative with a strip of material.

It is a further object of the present invention to pro vide improved strip thickness control apparatus operative with a strip of material for controlling the thickness taper or variations, if any, that may be desired.

It is another object of the present invention to provide improved strip thickness control apparatus operative with a rolling mill or like device for better controlling any desired variations in the thickness of that strip as a function of the length of the strip.

It is a different object of the present invention to provide improved strip thickness or gauge control apparatus for effecting any desired changes or variations, if any, in the strip thickness with regard both to the improved accuracy of the operation relative to the amount of each individual change and with regard to the improved accuracy of the lengthwise or longitudinal positioning of each such change.

These and other objects of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, wherein:

FIGURE 1 is a diagrammatic showing of control apparatus in accordance with the present invention; and

FIG. 2 illustrates the strip thickness taper or variation control that may be provided with the present control apparatus.

In FIG. 1 there is shown a strip of material 10, the thickness of which is determined by a rolling mill or like device 11 including an upper roller member 12 and a lower roller member 14. A screwdown device 16 is operative with said roller members 12 and 14 to vary the spacing between said roller members and therefore to vary the thickness of the strip 11 passing between the roller members 12 and 14. A screwdown motor 18 is operative with the screwdown device 16 for controlling the operation of said screwdown device 16, as well known to persons skilled in this particular art. A supply generator 29 is connected to energize the screwdown motor 1.8 and includes a control field winding 22 energized by a screwdown control device 24 that is responsive to the output signal generated by a pilot generator 26, operatively connected to the screwdown motor 18, and the voltage drop across a potentiometer device 28 having an adjustable tap 30. The potentiometer device 28 is energized by a pilot generator 32 operatively connected to the mill motor 34 that is operative with the roller members 12 and 14- for controlling the operating speed of the rolling mill and thereby the movement speed of the strip between the roller members 12 and 14.

A conventional control arrangement including a supply generator 36 connected to energize a mill motor 34 including a control field 38, with said generator 36 having a control field 40 energized by the well known mill speed control 42.

A pulse generator 44 is operatively connected to the 3,031,553 Patented Mar. 19, 1963 mill motor 34 for providing a plurality of pulses having a time interval determined by the speed of the mill 11 and thusly the movement speed of the strip 10 through the rolling mill. The output pulses from the generator 44 are supplied to a pulse counter 46, and in addition, control pulses are supplied from a program or scheduling control 48 as determined by a predetermined desired schedule of the thickness of the strip III which may, for example, be supplied by a punched card 50 or like input control device. The pulse counter 46 is operative with a subsequent strip taper control device 52 connected to energize the control field winding 54 of a booster generator 56 connected in series with control circuit arrangernent including the screwdown control 24, the pilot generator 26 and the voltage drop across the potentiometer 28 as shown in FIG. 1.

In FIG. 2 there is shown a cross section of the strip 10 illustrating a first rate of taper which may, for example, be at a negative number of inches for any predetermined length of the strip 10. The second rate of taper is also shown as a negative number of inches per foot of the strip. The third rate of taper is illustrated as a slightly positive number of inches per feet. The fourth rate of taper is a slightly greater positive number of inches per foot length of strip, and the fifth rate of taper shown is a positive number of inches per foot length of strip, but decreased as compared to the fourth rate of taper. In this regard, the showing of FIG. 2 is intended to be merely illustrative of the taper control obtainable with the present control apparatus and it should be understood that, if desired, a zero rate of taper may be provided or a maximum rate of taper as determined by the response time of the screwdown device 16 and its control motor 18. Also,,the various taper rates may apply for espectively different lengths of the strip.

In the operation of the present control apparatus, the screwdown device 16 may be initially set for an initial rate of taper by a human operator by suitable initial adjustments of the contact arm 30 on the potentiometer 28 to effect a predetermined fixed taper of thickness variation relative to a predetermined length of strip or a predetermined travel of the strip through the roller members 12 and 14.

The pulse counter 46 is operative to receive a predetermined number of pulses from the pulse generator 44, and then to pass a first thickness control signal from the program control 48 to the strip taper control device 52 for effecting the second taper rate at any desired variation in the strip thickness of the strip 11 In this regard, if, for example, the pulse counter 46 is responsive to ten pulses from the pulse generator 44, then after ten pulses have been received from the pulse generator 44, the pulse counter will initiate the second taper rate in accordance with information received from the program control 48. At the end of a second group of a predetermined number of pulses, say ten pulses, the pulse counter 46 will pass the third taper rate control signal in accordance with information received from the program control 48 and supply this latter thickness control information to the strip thickness taper control device 5-2 for effecting the desired thickness change of the strip 10. In this way, each of any desired number of individual counters provided within the pulse counter 46 will effectively measure a predetermined length of the strip 10 passing between the roller members 12 and 14 and in accordance with the length of the strip 19 a change in the taper rate will be effected as desired and as controlled by the program control i8 and the punched information card 53.

In this regard, it should be understood that. the various counters within the pulse counter 46 can be adjusted as desired such that the first pulse counter responds to a first group of ten pulses and then the second pulse counter responds to a succeeding second group of three pulses and then a third pulse counter may respond to a succeeding third group of an additional five pulses and so forth as may be desired.

The operation of each succeeding pulse counter Within the pulse counter 46 is operative to remove any previous taper control signal that may have been applied by a previous counter and supplies its own new taper control signal from the program control 48 to the strip thickness taper control device 52 for controlling the variable taper rate boost generator 56. The latter generator 56 inserts a positive or negative control signal in the speed matching circuit arrangement including the mill speed signal providing potentiometer 28 and the screwdown speed sensing pilot generator 26 connected in series with the screwdown control 24 operative to vary the screwdown device 16 through the screwdown motor 18, to effect any desired taper rate or thickness change in accordance with the taper control signal received from the program control 48.

More specifically, the output voltage from the mill speed pilot generator 32 may be in the order of plus 100 volts, and the settling of the contact arm 30 on the potentiometer 28 may be such as to provide a basic taper rate setting as indicated by a voltage drop of plus 40 volts. The screwdown speed sensing pilot generator 26 may be operative to supply a plus 40 volt signal which bucks or opposes the voltage drop across the potentiometer 28. The output signal from the taper rate booster generator 56 may be in the order of plus or minus volts such that the screwdown control 24 senses any voltage diflierence in the series circuit arrangement and including the opposed control signals from the respective pilot generators 26 and 32 and the taper control signal being supplied by the variable rate booster generator 56.

In this manner, the screwdown speed and thereby the thickness or" the strip 10 is changed in accordance with the output signals received from the generator 56 to thereby modify the strip thickness taper rate as determined by the setting of the contact arm 30 on the poentiometer 28.

- The respective taper rate output signals supplied by the generator 56 may be preset by suitable controls associated with each pulse counter unit within the pulse counter 46 as well known to persons skilled in this particular art to give the desired taper rate booster generator output signals of either polarity and over the complete strip length range desired. Thusly, the taper rate may be either positively or negatively changed and can be set in either direction at any taper rate within the range of the mill capacity. It should be readily apparent to persons skilled in this art that any desired number of pulse counter units within the pulse counter 10 may be provided such that the control apparatus may thereby provide any desired number of taper rate corrections such as the five taper rate changes illustratively shown in FIG. 2.,

The control apparatus shown in FIG. 1 is operative to introduce a change in the taper rate or the thickness change rate at any desired incremental length of the strip 10 passing through the rolling mill and, for example, the taper rate may be changed at each six inch interval along the length of the strip it}, which incremental length may be predetermined by the operator in accordance With the predetermined number of pulses required from the pulse generator 44 to cause a taper rate change to be effected by the strip thickness taper control device 52 operative through the generator 56. The number of taper rate changes is determined by the number of individual counter units provided Within the pulse counter 46. The pulse generator 44 may comprise a conventional rotating type of switch device which is coupled to the mill motor 34 and opens and closes a switch member to provide a pulse for every desired incremental length, such as six inches, of the strip 10 passing through the mill 11, including the roller members 12 and 14. The pulse counter 46 may, for example, comprise any desired number of magnetic pulse counters which are actuated by the pulses from the pulse generator 44 as well known to persons skilled in this art. In this regard, any individual counter unit or combination of counter units can be set by the operator to initiate a change in taper rate at any desired count or number of pulses received from the pulse generator 447 The actual taper rate or thickness change is varied by the booster generator 56, which modifies the speed reference signal Within the speed control circuit arrangement including the pilot generator 26, coupled to the screwdown motor l8, and the potentiometer 2S, responsive to the output signal from the pilot generator 32 coupled to the mill motor 34.

If desired, a variable coupling arrangement such as a variable gear arrangement or the like may be included between the pulse generator 44 and the mill motor 34 for providing a count rate variation to operate in conjunction with the rotating pulse generator 44 to permit any desired additional variation of the incremental length of the strip It required between the pulses supplied by the pulse generator 44.

It should be further understood that the program control 48 may include a conventional digital card reader device and a digital-to-analog converter device for providing an analog strip thickness control signal that is supplied to the strip thickness taper control device 52 as de termined by a gating action of the pulse counter 46.

Although the present invention has been described with a certain degree of particularity, it should be understood that the present disclosure has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts may be resorted to Without departing from the scope and the spirit of the present invention.

I claim as my invention:

1. In strip thickness control apparatus for a strip rolling mill including a thickness control device for con trolling the thickness of the strip moving through said mill, the combination of a first control signal source operatively connected to said mill for providing a first control signal in accordance with the operative speed of said mill, 2. second control signal source operatively connected to said thickness control device for providing a second control signal in accordance with a predetermined operation of said thickness control device, a third control signal source operative to provide a third control signal in accordance with a predetermined desired thickness control of said strip, with said third control signal source including a pulse generator device operatively connected to said mill for generating a plurality of control pulses in accordance with the operative speed of said mill, and with said third control signal source being responsive to said plurality of pulses for providing said third control signal as a function of the operating speed of said mill, with said thickness control device being responsive to a predetermined relationship between said first, second and third control signals for controlling the thickness of said strip as the strip moves through said rolling mill.

2. In strip thickness control apparatus for a strip rolling mill including a strip thickness control device, the combination of a first control member operatively connected to said mill for providing a first control signal in accordance with the movement velocity of said strip through said mill, a second control member operatively connected to said strip thickness control device for providing a second control signal in accordance with a predetermined operation of said thickness control device, and a strip thickness scheduling device including a pulse source operatively connected to said rolling mill for providing a plurality of pulses as a function of the movement of said strip through said mill, with said strip thickness scheduling device being operative to provide a third control signal in accordance with a predetermined desired thickness pattern for said strip and as a function of said pulses, with said strip thickness control device being responsive to a predetermined relationship between said first, second and third control signals for controlling the thickness of said strip relative to the passage of the strip through said mill.

References Cited in the file of this patent 6 Cook Sept. 2, 1941 Stoltz ,Oct. 6, 1942 Cook Feb. 29, 1944 Seid et a1. Jan.. 9, 1951 Cozzo Oct. 20, 1953 Zeitlin Aug. 24, 1954 

2. IN STRIP THICKNESS CONTROL APPARATUS FOR A STRIP ROLLING MILL INCLUDING A STRIP THICKNESS CONTROL DEVICE, THE COMBINATION OF A FIRST CONTROL MEMBER OPERATIVELY CONNECTED TO SAID MILL FOR PROVIDING A FIRST CONTROL SIGNAL IN ACCORDANCE WITH THE MOVEMENT VELOCITY OF SAID STRIP THROUGH SAID MILL, A SECOND CONTROL MEMBER OPERATIVELY CONNECTED TO SAID STRIP THICKNESS CONTROL DEVICE FOR PROVIDING A SECOND CONTROL SIGNAL IN ACCORDANCE WITH A PREDETERMINED OPERATION OF SAID THICKNESS CONTROL DEVICE, AND A STRIP THICKNESS SCHEDULING DEVICE INCLUDING A PULSE SOURCE OPERATIVELY CONNECTED TO SAID ROLLING MILL FOR PROVIDING A PLURALITY OF PULSES AS A FUNCTION OF THE MOVEMENT OF SAID STRIP THROUGH SAID MILL, WITH SAID STRIP THICK- 